Image capturing apparatuses such as digital cameras, digital video cameras, and so on, which use CCDs, CMOS APSs, and so on as their image sensors and record captured images, have been sold for some time. Such image sensors attempt to improve the image quality by increasing the number of pixels. For this reason, the surface area of each pixel for which the image sensor is configured has been decreasing year after year, and the surface area of the light-receiving section thereof has also decreased as a result. A decrease in the surface area of the light-receiving section also leads to a decrease in the sensitivity, thus an image sensor in which the light-collection characteristics are improved by providing a light guide for guiding light into the light-receiving section between the incident surface and the light-receiving section has been proposed (see Japanese Patent Laid-Open No. 4-73532).
Incidentally, image sensors are configured with multiple pixels being arrayed two-dimensionally, and these pixels include active pixels, whose light-receiving sections are open, and OB (optical black) pixels, which are shielded. It is desirable for such OB pixels to have the same characteristics as the active pixels, but it is known that a phenomenon called an “OB level difference” occurs. That is, the OB pixels are shielded by a shielding member such as aluminum, which causes parasitic capacitance to arise between the photodiode and the shielding member; this in turn results in different surface levels between the active pixels in the OB pixels (see Japanese Patent Laid-Open No. 2005-175930).
With image sensors that have light guides as mentioned earlier, the OB pixels often do not have light guides, which is problematic in that OB level differences occur more easily. In order to solve this problem, an image sensor in which light guides are embedded in the OB pixels as well has been proposed (see Japanese Patent Laid-Open No. 2007-141873).
The technique disclosed in Japanese Patent Laid-Open No. 2007-141873 is a useful technique to eliminate OB level differences. However, because the size of the light guides for OB pixels and the size of the light guides for active pixels are different, there is nevertheless the possibility that a small degree of OB level difference will remain. Although Japanese Patent Laid-Open No. 2007-141873 does mention using the same shape for the light guides as a valid means to eliminate this small degree of remaining OB level difference, a detailed structure to realize such a means is not disclosed therein.